<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">

    <title></title>
    <style>
        #parent{
            height: 150px;
            line-height: 30px;  /*与height等值*/
            background: #ff2e21;
        }
        .son{
            background-color: #00ff00;
        }
    </style>
</head>
<body>

<div id="parent">
    <span class="son">
        儿子
    </span>
    <span class="son">
        儿子
    </span>
    <span class="son">
        儿子
    </span>
</div>
</body>
</html>